/*
** Copyright (c) 2006 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License version 2 as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
** General Public License for more details.
**
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA 02111-1307, USA.
**
** Author contact information:
** drh@hwaci.com
** http://www.hwaci.com/drh/
**
*******************************************************************************
**
** Routines for encoding and decoding text.
*/
#include "config.h"
#include "encode.h"
/*
** Make the given string safe for HTML by converting every "<" into "<",
** every ">" into ">" and every "&" into "&". Return a pointer
** to a new string obtained from malloc().
**
** We also encode " as " so that it can appear as an argument
** to markup.
*/
char *htmlize(const char *zIn, int n){
int c;
int i = 0;
int count = 0;
char *zOut;
if( n<0 ) n = strlen(zIn);
while( i<n && (c = zIn[i])!=0 ){
switch( c ){
case '<': count += 4; break;
case '>': count += 4; break;
case '&': count += 5; break;
case '"': count += 6; break;
default: count++; break;
}
i++;
}
i = 0;
zOut = malloc( count+1 );
if( zOut==0 ) return 0;
while( n-->0 && (c = *zIn)!=0 ){
switch( c ){
case '<':
zOut[i++] = '&';
zOut[i++] = 'l';
zOut[i++] = 't';
zOut[i++] = ';';
break;
case '>':
zOut[i++] = '&';
zOut[i++] = 'g';
zOut[i++] = 't';
zOut[i++] = ';';
break;
case '&':
zOut[i++] = '&';
zOut[i++] = 'a';
zOut[i++] = 'm';
zOut[i++] = 'p';
zOut[i++] = ';';
break;
case '"':
zOut[i++] = '&';
zOut[i++] = 'q';
zOut[i++] = 'u';
zOut[i++] = 'o';
zOut[i++] = 't';
zOut[i++] = ';';
break;
default:
zOut[i++] = c;
break;
}
zIn++;
}
zOut[i] = 0;
return zOut;
}
/*
** Encode a string for HTTP. This means converting lots of
** characters into the "%HH" where H is a hex digit. It also
** means converting spaces to "+".
**
** This is the opposite of DeHttpizeString below.
*/
static char *EncodeHttp(const char *zIn, int n, int encodeSlash){
int c;
int i = 0;
int count = 0;
char *zOut;
int other;
# define IsSafeChar(X) \
(isalnum(X) || (X)=='.' || (X)=='$' || (X)=='-' || (X)=='_' || (X)==other)
if( zIn==0 ) return 0;
if( n<0 ) n = strlen(zIn);
other = encodeSlash ? 'a' : '/';
while( i<n && (c = zIn[i])!=0 ){
if( IsSafeChar(c) || c==' ' ){
count++;
}else{
count += 3;
}
i++;
}
i = 0;
zOut = malloc( count+1 );
if( zOut==0 ) return 0;
while( n-->0 && (c = *zIn)!=0 ){
if( IsSafeChar(c) ){
zOut[i++] = c;
}else if( c==' ' ){
zOut[i++] = '+';
}else{
zOut[i++] = '%';
zOut[i++] = "0123456789ABCDEF"[(c>>4)&0xf];
zOut[i++] = "0123456789ABCDEF"[c&0xf];
}
zIn++;
}
zOut[i] = 0;
return zOut;
}
/*
** Convert the input string into a form that is suitable for use as
** a token in the HTTP protocol. Spaces are encoded as '+' and special
** characters are encoded as "%HH" where HH is a two-digit hexidecimal
** representation of the character. The "/" character is encoded
** as "%2F".
*/
char *httpize(const char *z, int n){
return EncodeHttp(z, n, 1);
}
/*
** Convert the input string into a form that is suitable for use as
** a token in the HTTP protocol. Spaces are encoded as '+' and special
** characters are encoded as "%HH" where HH is a two-digit hexidecimal
** representation of the character. The "/" character is not encoded
** by this routine.
*/
char *urlize(const char *z, int n){
return EncodeHttp(z, n, 0);
}
/*
** Convert a single HEX digit to an integer
*/
static int AsciiToHex(int c){
if( c>='a' && c<='f' ){
c += 10 - 'a';
}else if( c>='A' && c<='F' ){
c += 10 - 'A';
}else if( c>='0' && c<='9' ){
c -= '0';
}else{
c = 0;
}
return c;
}
/*
** Remove the HTTP encodings from a string. The conversion is done
** in-place. Return the length of the string after conversion.
*/
int dehttpize(char *z){
int i, j;
/* Treat a null pointer as a zero-length string. */
if( !z ) return 0;
i = j = 0;
while( z[i] ){
switch( z[i] ){
case '%':
if( z[i+1] && z[i+2] ){
z[j] = AsciiToHex(z[i+1]) << 4;
z[j] |= AsciiToHex(z[i+2]);
i += 2;
}
break;
case '+':
z[j] = ' ';
break;
default:
z[j] = z[i];
break;
}
i++;
j++;
}
z[j] = 0;
return j;
}
/*
** The "fossilize" encoding is used in the headers of records
** (aka "content files") to escape special characters. The
** fossilize encoding passes most characters through unchanged.
** The changes are these:
**
** space -> \s
** tab -> \t
** newline -> \n
** cr -> \r
** formfeed -> \f
** vtab -> \v
** nul -> \0
** \ -> \\
**
** The fossilize() routine does an encoding of its input and
** returns a pointer to the encoding in space obtained from
** malloc.
*/
char *fossilize(const char *zIn, int nIn){
int n, i, j, c;
char *zOut;
if( nIn<0 ) nIn = strlen(zIn);
for(i=n=0; i<nIn; i++){
c = zIn[i];
if( c==0 || isspace(c) || c=='\\' ) n++;
}
n += nIn;
zOut = malloc( n+1 );
if( zOut ){
for(i=j=0; i<nIn; i++){
int c = zIn[i];
if( c==0 ){
zOut[j++] = '\\';
zOut[j++] = '0';
}else if( c=='\\' ){
zOut[j++] = '\\';
zOut[j++] = '\\';
}else if( isspace(c) ){
zOut[j++] = '\\';
switch( c ){
case '\n': c = 'n'; break;
case ' ': c = 's'; break;
case '\t': c = 't'; break;
case '\r': c = 'r'; break;
case '\v': c = 'v'; break;
case '\f': c = 'f'; break;
}
zOut[j++] = c;
}else{
zOut[j++] = c;
}
}
zOut[j] = 0;
}
return zOut;
}
/*
** Decode a fossilized string in-place.
*/
void defossilize(char *z){
int i, j, c;
for(i=j=0; z[i]; i++){
c = z[i];
if( c=='\\' && z[i+1] ){
i++;
switch( z[i] ){
case 'n': c = '\n'; break;
case 's': c = ' '; break;
case 't': c = '\t'; break;
case 'r': c = '\r'; break;
case 'v': c = '\v'; break;
case 'f': c = '\f'; break;
case '0': c = 0; break;
case '\\': c = '\\'; break;
default: c = z[i]; break;
}
}
z[j++] = c;
}
z[j] = 0;
}
/*
** The characters used for HTTP base64 encoding.
*/
static unsigned char zBase[] =
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~";
/*
** Encode a string using a base-64 encoding.
** The encoding can be reversed using the <b>decode64</b> function.
**
** Space to hold the result comes from malloc().
*/
char *encode64(const char *zData, int nData){
char *z64;
int i, n;
if( nData<=0 ){
nData = strlen(zData);
}
z64 = malloc( (nData*4)/3 + 6 );
for(i=n=0; i+2<nData; i+=3){
z64[n++] = zBase[ (zData[i]>>2) & 0x3f ];
z64[n++] = zBase[ ((zData[i]<<4) & 0x30) | ((zData[i+1]>>4) & 0x0f) ];
z64[n++] = zBase[ ((zData[i+1]<<2) & 0x3c) | ((zData[i+2]>>6) & 0x03) ];
z64[n++] = zBase[ zData[i+2] & 0x3f ];
}
if( i+1<nData ){
z64[n++] = zBase[ (zData[i]>>2) & 0x3f ];
z64[n++] = zBase[ ((zData[i]<<4) & 0x30) | ((zData[i+1]>>4) & 0x0f) ];
z64[n++] = zBase[ ((zData[i+1]<<2) & 0x3c) ];
}else if( i<nData ){
z64[n++] = zBase[ (zData[i]>>2) & 0x3f ];
z64[n++] = zBase[ ((zData[i]<<4) & 0x30) ];
}
z64[n] = 0;
return z64;
}
/*
** This function treats its input as a base-64 string and returns the
** decoded value of that string. Characters of input that are not
** valid base-64 characters (such as spaces and newlines) are ignored.
**
** Space to hold the decoded string is obtained from malloc().
**
** The number of bytes decoded is returned in *pnByte
*/
char *decode64(const char *z64, int *pnByte){
char *zData;
int n64;
int i, j;
int a, b, c, d;
static int isInit = 0;
static int trans[128];
if( !isInit ){
for(i=0; i<128; i++){ trans[i] = 0; }
for(i=0; zBase[i]; i++){ trans[zBase[i] & 0x7f] = i; }
isInit = 1;
}
n64 = strlen(z64);
while( n64>0 && z64[n64-1]=='=' ) n64--;
zData = malloc( (n64*3)/4 + 4 );
for(i=j=0; i+3<n64; i+=4){
a = trans[z64[i] & 0x7f];
b = trans[z64[i+1] & 0x7f];
c = trans[z64[i+2] & 0x7f];
d = trans[z64[i+3] & 0x7f];
zData[j++] = ((a<<2) & 0xfc) | ((b>>4) & 0x03);
zData[j++] = ((b<<4) & 0xf0) | ((c>>2) & 0x0f);
zData[j++] = ((c<<6) & 0xc0) | (d & 0x3f);
}
if( i+2<n64 ){
a = trans[z64[i] & 0x7f];
b = trans[z64[i+1] & 0x7f];
c = trans[z64[i+2] & 0x7f];
zData[j++] = ((a<<2) & 0xfc) | ((b>>4) & 0x03);
zData[j++] = ((b<<4) & 0xf0) | ((c>>2) & 0x0f);
}else if( i+1<n64 ){
a = trans[z64[i] & 0x7f];
b = trans[z64[i+1] & 0x7f];
zData[j++] = ((a<<2) & 0xfc) | ((b>>4) & 0x03);
}
zData[j] = 0;
*pnByte = j;
return zData;
}
/*
** The base-16 encoding using the following characters:
**
** 0123456789abcdef
**
*/
/*
** The array used for encoding
*/ /* 123456789 12345 */
static const char zEncode[] = "0123456789abcdef";
/*
** Encode a N-digit base-256 in base-16. Return zero on success
** and non-zero if there is an error.
*/
int encode16(const unsigned char *pIn, unsigned char *zOut, int N){
int i;
for(i=0; i<N; i++){
*(zOut++) = zEncode[pIn[0]>>4];
*(zOut++) = zEncode[pIn[0]&0xf];
}
*zOut = 0;
return 0;
}
/*
** An array for translating single base-16 characters into a value.
** Disallowed input characters have a value of 64. Upper and lower
** case is the same.
*/
static const char zDecode[] = {
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 64, 64, 64, 64, 64, 64,
64, 10, 11, 12, 13, 14, 15, 64, 64, 1, 64, 64, 1, 64, 64, 0,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 10, 11, 12, 13, 14, 15, 64, 64, 1, 64, 64, 1, 64, 64, 0,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
};
/*
** Decode a N-character base-16 number into base-256. N must be a
** multiple of 2. The output buffer must be at least N/2 characters
** in length
*/
int decode16(const unsigned char *zIn, unsigned char *pOut, int N){
int i, j;
if( (N&1)!=0 ) return 1;
for(i=j=0; i<N; i += 2, j++){
int v1, v2, a;
a = zIn[i];
if( (a & 0x80)!=0 || (v1 = zDecode[a])==64 ) return 1;
a = zIn[i+1];
if( (a & 0x80)!=0 || (v2 = zDecode[a])==64 ) return 1;
pOut[j] = (v1<<4) + v2;
}
return 0;
}
/*
** Return true if the input string contains only valid base-16 digits.
** If any invalid characters appear in the string, return false.
*/
int validate16(const char *zIn, int nIn){
int c, i;
for(i=0; i<nIn && (c = zIn[i])!=0; i++){
if( c & ~0x7f ) return 0;
if( zDecode[c]>63 ) return 0;
}
return 1;
}
/*
** The input string is a base16 value. Convert it into its canonical
** form. This means that digits are all lower case and that conversions
** like "l"->"1" and "O"->"0" occur.
*/
void canonical16(char *z, int n){
while( *z && n-- ){
*z = zEncode[zDecode[(*z)&0x7f]&0x1f];
z++;
}
}